Methods for forming conductive vias in semiconductor device components

ABSTRACT

A method for forming conductive vias in a substrate of a semiconductor device component includes forming one or more holes, or apertures or cavities, in the substrate so as to extend only partially through the substrate. A barrier layer, such as an insulative layer, may be formed on surfaces of each hole. Surfaces within each hole may be coated with a seed layer, which facilitates adhesion of conductive material within each hole. Conductive material is introduced into each hole. Introduction of the conductive material may be effected by deposition or plating. Alternatively, conductive material in the form of solder may be introduced into each hole.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a continuation of U.S. patent application Ser. No.11/717,437, filed Mar. 12, 2007, pending, which application is adivisional of U.S. patent application Ser. No. 10/668,914, filed Sep.23, 2003, now U.S. Pat. No. 7,345,350, issued Mar. 18, 2008, the entiredisclosures of each of which are hereby incorporated herein by thisreference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates generally to semiconductor fabrication.More particularly, the present invention relates to methods for makingelectrical interconnects from one surface of a substrate of asemiconductor component to the opposite surface of the substrate of thesemiconductor component and, more particularly, to methods forfabricating a through-via in a wafer, interposer, or other substrate.

2. State of the Art

Semiconductor chips may be produced with integrated circuits on bothsides of the chip or may be designed to connect to or interact withother electronic components or other semiconductor chips. Interposersmay be utilized for interfacing two electrical components, such as asemiconductor device and a printed circuit board, and contactor boardsmay be used to interface a semiconductor wafer and a probe card fortesting the dice on the semiconductor wafer. Semiconductor chips may beformed of semiconductor wafer or other bulk substrate material, whileinterposers and contactor boards may be formed of silicon, ceramic orpolymeric substrates.

Conductively lined or filled holes (hereinafter “vias”) are used forconnecting an integrated circuit on one side of a chip to: an integratedcircuit on the other side of the chip, a ground or other bias voltage,another electronic component or an integrated circuit on another chip.Vias are also used for providing electrical communication betweenstructures disposed on opposing sides of an interposer or contactorboard, wherein the structures may align with contact pads or otherstructures of electrical components and establish electrical connectionbetween the various components.

The continued miniaturization of integrated circuits results in viashaving increasingly higher aspect ratios, which term refers to the ratioof height or length to width or diameter of the via. One factorcontributing to the increasingly higher aspect ratios is that the widthof vias is continually getting smaller. Known processes used for fillingthe high-aspect-ratio vias in stacked chips, interposers and contactorboards, which are typically about fifty microns wide, have difficultyfilling these vias without forming voids or keyholes in the via.Conventionally, the vias may be lined with a seed layer of a metal, suchas copper, using chemical vapor deposition (CVD) or physical vapordeposition (PVD), whereafter the seed layer is coated by electroplating.As the aspect ratios of the vias get higher, it becomes more difficultto cause the plating material to line or fill the vias without vugs,voids, or keyholes therein which adversely affect the conductivity ofthe via.

Referring to FIG. 1, there is shown a cross-section of a substrategenerally at 10. The substrate includes a via 12 that is filled using anelectroplating process known in the art. The interior of the via 12 iscoated with a metal layer 14, which has been deposited using theelectroplating process. Electroplating is an electrochemical process bywhich metal, in ionic form in solution, is deposited on a substrateimmersed in a bath containing the ionic form of the metal. A current ispassed from an anode through the electroplating solution such that themetal ions are deposited on the cathode provided by a seed layer ofmetal of the substrate. As illustrated, a surface of the metal layer 14is uneven and when the via 12 is filled to completion, the unevensurface may result in the formation of one or more voids in the contactmass filling the via. In other known processes, the via may be filled byan electroless plating process. In electroless plating, a seed layer maybe formed by, for example, using plasma enhanced chemical vapordeposition (PECVD). The seed layer is coated by a metal layer by placingthe substrate in a bath that contains metal ions in aqueous solution anda chemical reducing agent such that the metal ions are deposited on theseed layer by a chemical reduction process.

FIG. 2 illustrates a cross-section of another substrate generally at 20.The substrate 20 includes a via 22 filled with a metal layer 24 usingelectroplating as known in the art. The metal layer 24 was depositedmore efficiently near the upper and lower surfaces of the substrate 20and resulted in the via 22 being substantially closed near the upper andlower surfaces of the substrate 20 while a middle portion of the via 22was left unfilled. The unfilled portion 26 of the via 22 is referred toas a keyhole and the presence of the keyhole detracts from theelectrical conductivity of the via 22.

In an attempt to avoid the formation of voids and keyholes in the via,other methods have been developed to fill the vias. FIG. 3 is across-section of a substrate generally at 30. The substrate 30 includesa via 32, being filled using electroless plating as known in the art.The substrate 30 is placed in a bath for an electroless plating process,also referred to as immersion plating. As illustrated, a metal layer 34is formed over a seed layer (not shown) on the sidewall of the via 32 bythe continuous deposition of metal until the via 32 is substantiallyfilled with the metal. However, the electroless deposition process ofFIG. 3 may result in voids or depressions being present in the via 32.Further, since electroless plating is relatively slow, i.e., the metal,such as nickel, is deposited at a maximum rate of approximately 20microns per hour, the extended time to complete the deposition processmay be undesirable. For instance, if the via is 70 μm wide, thedeposition process would take about one and three-quarter hours todeposit about 35 μm of metal on the interior of the via 32 (70 μm/2) asthe metal layer 34 grows inwardly toward the center of the via tocompletely fill the via 32.

In another attempt to avoid the formation of voids and keyholes in avia, an electroless bottom fill process as known in the art may be used.FIG. 4 illustrates a cross-section of a substrate generally at 40. Thesubstrate 40 includes a via 42 and a layer of a metal 44 deposited on abottom 46 of the via 42 and growing towards a top 48 of the via 42. Thebottom 46 of the via 42 may comprise a suitable metal such as copper(Cu), nickel (Ni) or tungsten (W). The approach of the bottom fillprocess is that by depositing the layer of metal 44 in one direction,upward, and not from the sides of the via 42 (as shown in FIG. 3), voidsand keyholes are not formed between layers of metal growing towards eachother. The bottom fill process may be performed with copper in anattempt to avoid keyhole formation in the via due to migration of thecopper. However, since the vias may be as deep as, e.g., 700 microns,and electroless plating deposits metal at the aforementioned relativelyslow rate, the process to completely fill the via is unacceptably timeconsuming. Electroplating from the bottom of a via is also known,wherein a conductor serving as a cathode is placed over the bottom of asubstrate, covering the bottoms of the vias. However, such an approachseverely limits the stage of wafer processing at which the via may befilled and may impose design limitations on other structures formed orto be formed on the substrate.

Accordingly, a need exists for an improved method for filling vias thatis faster than known processes, does not leave voids, depressions, orkeyholes in the filled via and is cost effective to manufacture.

BRIEF SUMMARY OF THE INVENTION

The present invention, in a number of embodiments, overcomes the abovedifficulties by providing a method for forming a conductive via in asemiconductor component and semiconductor components resultingtherefrom. The methods of forming conductive vias of the presentinvention are faster than known processes since the conductive via isnot completely filled with an electroplated or electroless plated metal.Further, the conductive vias of the present invention include an annularlayer of conductive material that is substantially free of vugs, voids,and keyholes such that the conductivity of the via is not compromised.

One exemplary embodiment of a method for forming a conductive via in asemiconductor component includes providing a substrate having a firstsurface and an opposing second surface. At least one hole extending fromthe first surface to the second surface of the substrate is formedthrough the substrate. A seed layer is applied to the first surface, thesecond surface and a sidewall defining the at least one hole formed inthe substrate. The seed layer overlying the first surface and theopposing second surface of the substrate is removed, leaving the seedlayer on the sidewall of the at least one hole. The seed layer on thesidewall is coated with a conductive layer and a conductive ornonconductive filler material is introduced into a remaining space inthe at least one hole.

In another exemplary embodiment, a second method for fabricating aconductive via through a substrate is also disclosed. The methodcomprises providing a substrate having a first surface and an opposingsecond surface. At least one cavity is formed in the first surface ofthe substrate. A conductive layer is applied over the first surface ofthe substrate and an exposed area of the substrate that defines the atleast one cavity. A filler material is introduced into a remaining spaceof the at least one cavity. The conductive layer and the filler materialintroduced into the at least one cavity are exposed on the opposingsecond surface of the substrate.

Yet another exemplary embodiment comprises an intermediate semiconductorcomponent including at least one conductive via precursor structure. Theintermediate semiconductor component includes a substrate having a firstsurface and an opposing second surface. The at least one conductive viaprecursor structure extends into the first surface of the substrate andterminates in the substrate before reaching the opposing second surface.The at least one via precursor structure includes an annular conductivelayer that extends from the first surface and circumscribes a conductiveor nonconductive filler material.

A further exemplary embodiment of the present invention comprises asemiconductor component including a substrate having a first surface andan opposing second surface and at least one conductive via extendingtherebetween. The at least one conductive via includes an annularconductive layer that extends from the first surface of the substrate tothe second surface of the substrate. A conductive or nonconductivefiller material is circumscribed by the annular conductive layer andextends from the first surface of the substrate to the opposing, secondsurface of the substrate.

The present invention also encompasses, in yet another embodiment, asystem including a microprocessor and at least one memory device incommunication with the microprocessor. The at least one memory devicecomprises a substrate having a first surface and an opposing, secondsurface and at least one conductive via extending therebetween. The atleast one conductive via includes an annular layer of conductivematerial extending from the first surface of the substrate to theopposing, second surface of the substrate. A conductive or nonconductivefiller material is circumscribed by the annular layer of the conductivematerial and extends from the first surface of the substrate to theopposing, second surface of the substrate. The memory device alsoincludes at least one bond pad overlying the at least one conductivevia.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

In the drawings, which illustrate what is currently considered to be thebest mode for carrying out the invention:

FIG. 1 is a cross-section of a via in a substrate filled using anelectroplating process as known in the art;

FIG. 2 illustrates a cross-section of a substrate having a viasubstantially filled using an electroplating process as known in theart;

FIG. 3 depicts a cross-section of a substrate having a via filled usingan electroless plating process as known in the art;

FIG. 4 is a cross-section of a substrate having a via filled using abottom fill process as known in the art;

FIGS. 5A through 5G illustrate acts of an exemplary embodiment of amethod for filling vias of the present invention;

FIGS. 6A through 6H illustrate acts of another exemplary embodiment of amethod for filling vias of the present invention;

FIGS. 7A and 7B depict acts of another embodiment of a method forforming vias of the present invention;

FIG. 8 depicts a semiconductor component having electrical interconnectsformed using the present invention; and

FIG. 9 is a schematic diagram of an electronic system incorporating theelectrical interconnects fabricated using the methods of the presentinvention.

DETAILED DESCRIPTION OF THE INVENTION

Generally, the present invention includes methods for manufacturingelectrical interconnects, i.e., vias, from one surface of a substrate tothe opposite surface of the substrate of a semiconductor component. Thevias may electrically connect various electrical structures of thesemiconductor component or may be used to electrically connect withother components. It will be apparent to those of ordinary skill in theart that the methods for fabricating vias of the present invention willalso be useful in manufacturing interposers and other substrates such ascontactor boards where electrical interconnects are desired. As usedherein, the term “semiconductor component” means and includes electroniccomponents fabricated from semiconductor wafers, other bulksemiconductor substrates, and other substrate materials susceptible tothe formation of vias therethrough in accordance with the presentinvention.

Referring to the accompanying drawings, wherein similar features andelements are identified by the same or similar reference numerals,various embodiments of methods for fabricating vias formed through thethickness of a wafer or other substrate are illustrated. It will beapparent to those of ordinary skill in the art that while the processesdescribed herein illustrate methods for fabricating vias, the actsdescribed herein comprise a portion of the entire fabrication process ofa semiconductor component and may be combined with other fabricationprocesses. As used herein, the term “substrate” will refer to anysupporting structure in which vias may be formed including, but notlimited to, semiconductor wafers, interposer substrates, contactorboards or other substrate-based structures.

The invention includes methods for fabricating a via through thethickness of a wafer or other substrate, wherein the via includes aconductive liner material and a filler material. The filler material maybe a conductive or nonconductive material. Referring now to drawing FIG.5A, there is shown a cross-section of a semiconductor componentgenerally at 100. The semiconductor component 100 includes a substrate112 having a first surface 114 and an opposing second surface 116. Thesubstrate 112 may comprise an unprocessed semiconductor wafer or othersubstrate, wherein the substrate may have various process layers formedthereon including one on more semiconductor layers or other structures.The substrate 112 may further include active portions or other operableportions located thereon fabricated by etching, deposition or otherknown techniques. The substrate 112 may further comprise an interposersubstrate for use between a test device and a semiconductor device to betested (contactor board) or between a memory device and system in apackage to provide routing among other substrates. In the exemplaryembodiment, the substrate 112 comprises a semiconductor material, suchas monocrystalline silicon. In other embodiments, the substrate 112 maycomprise polycrystalline silicon, germanium, silicon-on-glass,silicon-on-sapphire, a ceramic, a polymer or a glass-filled, epoxy resinmaterial. The substrate 112 may also comprise any other known substratematerial.

The semiconductor component 100 has a via 118 extending from the firstsurface 114 of the substrate 112 to the second surface 116. In theexemplary embodiment, the via 118 has a substantially cylindrical shapeand is defined by an inner surface or sidewall 120. In otherembodiments, the via 118 may have other shapes, such as an hour glassshape or any other known shape for the formation of vias. The portionsof the substrate 112 that circumscribe an uppermost edge 122 and alowermost edge 124 of the via 118 are illustrated in broken lines. Forease of illustration, the uppermost edge 122 and the lowermost edge 124of the via 118 will be omitted from subsequent drawings.

In the illustrated embodiment, the via 118 is formed in the substrate112 by laser ablation and may have a representative diameter of fromabout 10 μm to 2 mils or greater. Typically, the via 118 will have adiameter of about 50 μm when the semiconductor component 100 is used forstacked chips, interposers, contactor boards or other known electroniccomponents. Since the ratio of the height to width of vias iscontinually decreasing with the continued miniaturization of integratedcircuits, it is contemplated that the via 118 may be formed to have adiameter of about 30 μm. It will be apparent to those of ordinary skillin the art that any known method of forming vias that is appropriate forthe type of substrate 112 used to form the semiconductor component 100may be used to form the via 118 including, without limitation, a dryetch such as a reactive ion etch (RIE) which can remove up to 5 μm ofsubstrate per minute depending on the type of substrate, photochemicaletching, or any other known via formation process. It will be furtherapparent to those of ordinary skill in the art that the diameter of thevia 118 and the thickness of the substrate 112 may be any desireddimension depending on the desired use of the semiconductor component100.

Once the via 118 has been formed in the substrate 112, the inner surface120 may be cleaned to remove any substrate material affected by the heatproduced by the laser ablation process. If desired, a TMAH (tetramethylammonium hydroxide) solution may be used to clean the via 118 afterformation, which can result in a squared cross-section for the via.

The cleaned inner surface 120 may be passivated by coating the innersurface 120 of the substrate 112 with an insulative layer 126 ofdielectric or insulative material appropriate for the type of materialof the substrate 112. The insulative layer 126 may comprisespin-on-glass, thermal oxide, PARYLENE™ polymer, silicon dioxide,silicon nitride, silicon oxynitride, a glass, i.e., borophosphosilicateglass, phosphosilicate glass or borosilicate glass, or any dielectrichaving a low dielectric constant known in the art. To accomplish thepassivation, the insulative layer 126 may be deposited to any desiredthickness using any known process including, without limitation,physical vapor deposition (PVD), CVD, low pressure chemical vapordeposition (LPCVD), rapid thermal nitridation (RTN), a spin-on-glass(SOG) process, flow coating or any other known process. In otherembodiments, the insulative layer 126 may comprise an insulatingpolymer, such as BT resin, polyimide, benzocyclobutene orpolybenzoxazole deposited using an injection or capillary process or avacuum draw. The insulative layer 126 may be, for example, of about 1 to5 μm in thickness. If the substrate 112 comprises an electricallyinsulating material, such as ceramic, the insulative layer 126 may beomitted.

As shown in FIG. 5B, a seed layer 128 of a conductive material isdeposited over the first surface 114 and second surface 116 of thesubstrate 112, and the inner surface 120 of the via 118, wherein theseed layer 128 coats the insulative layer 126 (shown in FIG. 5A). Forease of illustration, the insulative layer 126 of drawing FIG. 5A isomitted from FIG. 5B and other subsequent drawings. In the illustratedembodiment, the seed layer 128 comprises titanium nitride (TiN) and isdeposited by CVD. Other materials that may be used as the seed layer 128include, without limitation, titanium (Ti), silicon nitride (Si₃N₄), apolysilicon, tantalum nitride (TaN), and copper. Other depositionprocesses that may be used to deposit the seed layer 128 include PVD,atomic layer deposition (ALD), PECVD, vacuum evaporation, andsputtering. It will be apparent that the selection of the type ofmaterial and deposition process utilized to deposit the seed layer 128will vary depending on the type of material used to form the electricalinterconnect through the via 118.

A portion of the seed layer 128 covering the first surface 114 andsecond surface 116 of the substrate 112 is removed to expose the firstsurface 114 and second surface 116 of the substrate 112 as illustratedin FIG. 5C. In the illustrated embodiment, the seed layer 128 is removedby an abrasive planarization process such as chemical mechanicalplanarization (CMP). However, the selective removal of the seed layer128 may be accomplished using any other known process such as a wet etchor a dry etch using an etchant appropriate for the type of materialmaking up the seed layer 128 after masking the portion of seed layer 128within the via 118.

The seed layer 128 may also be covered with a layer of resist 129. Theresist 129 is applied to the seed layer 128 before CMP such that theresist 129 prevents particles produced by the CMP process from beingdeposited in the via 118. Once the CMP process is finished, the resist129 is removed using known techniques and produces a pristine seed layer128 surface for the selective deposition of conductive material.

In another exemplary embodiment, the first surface 114 and the secondsurface 116 of the substrate 112 may be coated with a nitride layer toprevent the seed layer 128 from being deposited on the first surface 114and the second surface 116 of the substrate 112 in order to preventpeeling which may occur depending on the type of conductive materialused to coat the surfaces of the substrate 112 and the type of substrate112 used. The via 118 may be masked to prevent the nitride layer frombeing deposited in the via 118 or the nitride layer may be applied onthe first surface 114 and second surface 116 of the substrate 112 beforethe via 118 is formed therein. In addition to using a nitride layer, itwill be apparent to those of ordinary skill in the art that any othermaterial that prevents the seed layer 128 from being deposited on thefirst surface 114 and the second surface 116 of the substrate 112 may beused.

The seed layer 128 is coated with a conductive layer 130 of metal asillustrated in FIG. 5D using an electroless deposition process. Theconductive layer 130 is deposited on the seed layer 128 and not on theexposed first and second surfaces 114 and 116 of the substrate 112 sincethe seed layer 128 was removed from (or never present on) these surfacesand the electroless deposition process requires the seed layer 128 fordeposition of the conductive layer 130. The selective removal of theseed layer 128 from the first surface 114 and the second surface 116 ofthe substrate 112 and leaving the seed layer 128 in the via 118 orselective deposition of the conductive layer 130 in the via obviates theneed for a subsequent CMP step to remove excess material. The selectivedeposition of the conductive layer 130 reduces the amount of metal usedas the conductive layer and, thus, decreases the cost of manufacturing.Further, the selective deposition of the conductive layer 130 in the via118 helps prevent adhesion issues that may occur when plating a thickconductive layer 130. Stresses that cause peeling on the conductivelayer 130 of the open first surface 114 and the open second surface 116of the substrate 112 are greater than the peeling stress inside the via118. The conductive layer 130 may comprise any type of metal including,but not limited to, nickel, cobalt, copper, silver, titanium, iridium,gold, tungsten, tantalum, molybdenum, platinum, palladium,nickel-phosphorus (NiP), palladium-phosphorus (Pd—P), cobalt-phosphorus(Co—P), a Co—W—P alloy, other alloys of the foregoing metals andmixtures thereof. The type and thickness of the metal to be used in theconductive layer 130 will vary depending on the desired conductivity anduse of the semiconductor component 100 which may be determined, at leastin part, by the resistance (R) of the metal or conductive layerexpressed by the equation R=ρL/A as known in the art.

By coating the seed layer 128 with the conductive layer 130 of asuitable metal, an annular conductive path is created through the via118. The electroless plating process forms a substantially conformalcoating in the via 118 that is substantially free of any voids orkeyholes. The conductive layer 130 formed from the electroless platingprocess will typically have a uniform thickness and a low porosity, willprovide corrosion protection and will be relatively hard. Theelectroless plating process is accomplished by placing the substrate 112into a bath containing an aqueous solution of the metal to be depositedin ionic form. The aqueous solution also includes a chemical reducingagent such that the metal may be deposited without the use of electricalenergy. The driving force for the reduction of the metal ions andsubsequent deposition in the electroless plating process is driven bythe chemical reducing agent. The reduction reaction is essentiallyconstant at all points on the seed layer 128 so long as the aqueoussolution is sufficiently agitated (for example, by ultrasound) to ensurethat a uniform concentration of metal ions and reducing agents aredistributed in the aqueous solution.

In a further exemplary embodiment, the conductive layer 130 is linedwith silver or gold using an immersion process, such as an immersionplating process. If the conductive layer 130 includes nickel or cobalt,the silver or gold lining will replace the nickel or cobalt since silverand gold are more noble than nickel and cobalt. The silver or goldlining will increase conductivity and aid in wetting the solder to helpensure a void-less fill of solder and continuous contact of solder withthe sidewalls of the via 118.

Since the seed layer 128 extends to a plane or level even with the firstsurface 114 and the second surface 116 of the substrate 112, thedeposition of the conductive layer 130 may result in a small portion 132of the conductive layer 130 extending beyond the plane of the firstsurface 114 or the second surface 116 of the substrate 112. The smallportion 132 may be removed, if desired, using CMP or other known removalprocesses such that the conductive layer 130 is substantially even withthe plane of the first surface 114 and the second surface 116 of thesubstrate 112 as illustrated in drawing FIG. 5E.

As illustrated in FIG. 5E, the via 118 has an opening 134 extending fromthe first surface 114 to the second surface 116 wherein the opening 134is circumscribed by the conductive layer 130. Although the electrolessplating process used to form the conductive layer 130 may incidentallyresult in minor depressions or voids in the conductive layer 130, thethickness of the conductive layer 130 required to accommodate thedesired conductivity should be of a dimension such that any voids ordepressions should not affect the conductivity. The opening 134 of thevia 118 is filled with a filler material 136 as illustrated in drawingFIG. 5F. By forming the conductive layer 130 to the desired thicknessand filling the remaining opening 134 of the via 118 with the fillermaterial 136, physical support is provided within the via for thesubstrate while the conductive path provided by conductive layer 130 ismaintained.

The filler material 136 may be a conductive or a nonconductive materialdepending on the desired conductivity of the filled via 118 and intendeduse of the semiconductor component 100. For instance, since theconductivity of the filled via 118 is at least minimally determined bythe material and thickness of the conductive layer 130, a nonconductivematerial may be used to fill the opening 134 of the via 118 ifconductive layer 130 provides an adequate conductive path. Nonlimiting,representative examples of substances that may be used for the fillermaterial 136 include silicon-containing fillers such as spin-on-glass(SOG) applied using a spin coat process for a nonconductive fillermaterial 136 or polysilicon applied using a diffusion process and dopedfor a conductive filler material 136. Solder paste applied with asqueegee and subsequently reflowed may also be used as a conductivefiller material 136. The solder paste may include eutectic solder,Cu—Sn—Ag, Sn—Ag, other known solder materials, or combinations thereof.Other filler materials 136 that may be used include, without limitation,a solder alloy screen printed in the opening 134, conductive andnonconductive polymers, metal-filled silicon, carbon-filled ink,isotropically or anisotropically conductive adhesives andconductor-filled epoxies, such as silver-filled epoxy paste.

If any of the filler material 136 extends beyond the plane of the firstsurface 114 or the second surface 116 of the substrate 112 after theopening 134 of the via 118 is filled, any protruding filler material 136may be removed using CMP or other known smoothing process such that bondpads 138 may be formed over one or both ends of the via 118 as known inthe art and shown in FIG. 5G. The filler material 136 provides physicalsupport to the bond pads 138 overlying the via 118. Although thesemiconductor component 100 in the exemplary embodiment is shown withone via 118, it will be apparent to those of ordinary skill in the artthat any number of vias 118 may be simultaneously formed, lined andfilled in the semiconductor component 100 using the disclosed process.

In another exemplary embodiment, a blind via may be used to form theconductive via of the present invention. A cross-section of asemiconductor component is shown generally at 200 in FIG. 6A. Thesemiconductor component 200 comprises a substrate 212 having a firstsurface 214 and an opposing second surface 216. The substrate 212 maycomprise an unprocessed semiconductor wafer or other substrate materialused in fabrication processes as previously described herein withreference to the substrate 112 of FIG. 5A.

The semiconductor component 200 includes a blind via 218 that partiallypenetrates the substrate 212 and substantially extends through thesubstrate 212 from the first surface 214 and wherein a bottom 213 of theblind via 218 terminates short of the second surface 216 of thesubstrate 212. The blind via 218 may be formed in the substrate 212using a laser ablation process or in any other manner as the via 118 wasformed in the substrate 112 as described herein with reference to FIG.5A. The blind via 218 is circumscribed by an inner surface or sidewall220 of the substrate 212. The portion of the substrate 212 thatcircumscribes an uppermost edge 222 of the blind via 218 is illustratedin broken lines which, for ease of illustration, is omitted fromsubsequent drawings.

In the exemplary embodiment of FIG. 6A, the blind via 218 may alsocomprise an opening in the substrate 212 that extends through thesubstrate 212 (substantially similar to the via 118 of FIG. 5A) that issealably covered or capped with a cover layer 225 and illustrated withphantom lines 224. The cover layer 225 substantially seals the blind via218 such that, in essence, the covered via is filled in substantiallythe same manner as the blind via 218. A seed layer (not shown) may thusalso be deposited on the cover layer 225 forming the bottom 213 of blindvia 218. In another exemplary embodiment, the cover layer 225 maycomprise a metal layer attached to the substrate 212 before the blindvia 218 is formed in the substrate 212. Laser ablation may then be usedto partially form the blind via 218, which is then completed using a dryetch which will stop on the metal of cover layer 225. The blind via 218may be insulated with a passivation layer (not shown) if required.

By forming the blind via 218 using the embodiment of FIG. 6A,contaminants and other process materials may be prevented from gettingon or contaminating a wafer chuck 217 or other support structure. Thewafer chuck 217 may be used to support the semiconductor component 200during the fabrication process and the illustration of the wafer chuck217 will be omitted from subsequent drawings.

The inner surface 220 of the blind via 218 may be cleaned to remove anydebris, residual material or substrate material adversely affected bythe formation of the blind via 218. The cleaned inner surface 220 may bepassivated by coating the inner surface 220 of the substrate 212 with alayer of dielectric or insulative material appropriate for the type ofsubstrate 212. For ease of illustration, the passivation layer is notdepicted in drawing FIG. 6A, but it will be apparent to those ofordinary skill in the art that the passivation layer of the blind via218 may be substantially similar to the insulative layer 126 asdescribed with reference to FIG. 5A. Further, depending on the materialof substrate 212, the passivation layer may be omitted.

Referring to FIG. 6B, the semiconductor component 200 is shown with aseed layer 228 of conductive metal formed on the first surface 214 ofthe substrate 212 and the inner surface 220 of the blind via 218. In theillustrated embodiment, the seed layer 228 is TiN and is deposited byCVD. However, the seed layer 228 may comprise any other material asdescribed herein with reference to the seed layer 128 of FIG. 5B.

The portion of the seed layer 228 covering the first surface 214 of thesubstrate 212 is removed by CMP to expose the first surface 214 of thesubstrate 212 as illustrated in FIG. 6C. It will be apparent that theseed layer 228 may be removed using any known process as previouslydescribed herein. A conductive layer 230 is deposited overlying the seedlayer 228 as illustrated in FIG. 6D using an electroless depositionprocess as previously described herein. The conductive layer 230 willnot adhere to the first surface 214 of the substrate 212 since no seedlayer 228 is present on the first surface 214 of the substrate 212. Theconductive layer 230 may comprise any conductive metal as describedherein with reference to the conductive layer 130 of FIG. 5D wherein thetype and thickness of the metal utilized in the conductive layer 230will vary depending on the desired conductivity and ultimate use of thesemiconductor component 200.

In another exemplary embodiment, a layer of resist 229 is placed overthe seed layer 228 before CMP. The presence of the resist 229 preventsparticles produced by the CMP process from contaminating the blind via218. After CMP, the resist 229 is removed using known techniques andresults in a pristine surface for the subsequent deposition of theconductive layer 230.

As the conductive layer 230 is deposited on the seed layer 228, aportion 232 of the conductive layer 230 may extend beyond a plane of thefirst surface 214 of the substrate 212. If this occurs, the portion 232of the conductive layer 230 extending beyond the plane of the firstsurface 214 may be removed as previously described herein with referenceto FIG. 5E and result in the semiconductor component 200 of FIG. 6E. Inanother exemplary embodiment, the portion 232 of the conductive layer230 extending above the plane of the first surface 214 of the substrate212 may be left in place and used, at least partially, to form at leasta portion of a bond pad (shown in FIG. 6H) subsequently constructed onthe first surface 214 of the substrate 212.

The conductive layer 230 may be lined with silver or gold using animmersion plating process in another exemplary embodiment. If theconductive layer 230 includes nickel or cobalt, the nickel or cobaltwill be replaced with the silver or gold since silver and gold are morenoble. The inclusion of the silver or gold lining in the conductivelayer 230 will also increase conductivity and aid in wetting the solder.

As shown in FIG. 6E, the blind via 218 includes an opening 234substantially surrounded by the conductive layer 230 that extends fromthe first surface 214 of the substrate 212 and substantially through thesubstrate 212 to and over the bottom 213 of the blind via 218. Theopening 234 of the blind via 218 is filled with a filler material 236 asillustrated with cross-hatching in FIG. 6F. The filler material 236 maycomprise a conductive or a nonconductive material depending on thedesired conductivity of the filled blind via 218 as previously describedherein with reference to FIG. 5F.

The second surface 216 of the substrate 212 is removed from thesemiconductor component 200 using an abrasive planarization process suchas CMP or any other known suitable removal process. Material of thesubstrate 212 is removed to a depth illustrated by broken line 240 inFIG. 6F such that the blind via 218 is exposed on the second surface 216of the substrate 212 as illustrated in FIG. 6G. Bond pads 238 are formedover opposing ends of the blind via 218 as is known in the art and asillustrated in FIG. 6H. In a variation of this exemplary embodiment, ifblind via 218 extended through the substrate 212 to cover layer 225, asdescribed with reference to FIG. 6A, the cover layer 225 may be removedto expose the blind via 218 lined with conductive layer 230 and filledwith filler material 236.

Another exemplary embodiment of acts in the methods of the presentinvention is depicted in FIGS. 7A and 7B. A semiconductor component isshown generally at 200′. The semiconductor component 200′ includes asubstrate 212 having a first surface 214 and an opposing, second surface216. A barrier layer 203 is formed on the first surface 214 of thesubstrate 212. The barrier layer 203 comprises a material that preventsa seed layer 228 from being deposited thereon. The barrier layer 203 maycomprise an oxide- or a nitride-containing material such as silicondioxide or silicon nitride. A blind via 218 is formed through thebarrier layer 203 and in the substrate 212. A seed layer 228 andconductive layer 230 are formed in the blind via 218, whereafter theremaining opening 234 of the blind via 218 is filled with the fillermaterial as previously discussed herein. The fabrication of theconductive blind via 218 may be completed as previously described.

Referring now to FIG. 8, there is shown a partial cross-section of asemiconductor component 300 that has been fabricated using the methodsof the present invention. The semiconductor component 300 includes asubstrate 312 with a conductive via 318. The conductive via 318 includesa filler material 336 and an annular conductive liner 330 that forms anelectrical connection between bonds pads 338 located on opposingsurfaces of the semiconductor component 300.

The semiconductor component 300 may include circuit traces 340 or otherinterconnects and contact structures to electrically connect the via 318to contact pads 342 or other conductive structures. The circuit traces340 or other conductive structures may also be used to connect circuitryof semiconductor component 300 to other circuits such as integratedcircuitry formed on an opposing side of substrate 312, to circuits ofanother semiconductor component disposed over or under semiconductorcomponent 300 in a stack, to an interposer, to a contactor board, or toa carrier substrate such as a motherboard or module board bearing othersemiconductor components such as a microprocessor. Further, the blanketmaterial layer from which bond pads 338 are formed may also be patternedto define the circuit traces 340 leading from the via 318 to the contactpads 342. The conductive via 318 thus may be used to electricallyconnect contact pads 342 on a first surface 314 of the substrate 312 tocontact pads 342 on a second surface 316 of the substrate 312.

As noted, the substrate 312 of the semiconductor component 300 may bedesigned and fabricated as an interposer for connecting varioussemiconductor components, as a semiconductor test substrate (contactorboard) or as a carrier substrate forming higher-level packaging to whichsemiconductor chips may be connected. If configured as a semiconductordevice with active circuitry, the bond pads 338 or contact pads 342 ofthe semiconductor component 300 may be arranged in a pattern thatcorresponds to that of terminal pads on a test or carrier substrate. Ifused as an interposer or contactor board, bond pads 338 or contact pads342 may be arranged in a pattern on one side of substrate 312 tocorrespond to terminal pads of a test or carrier substrate and on theother side to correspond to bond pad or other I/O locations on asemiconductor device to be contacted.

Referring now to FIG. 9, there is shown an embodiment of a system 400including the conductive vias of the present invention. The system 400comprises at least one memory device 402, such as a static random accessmemory (SRAM), dynamic random access memory (DRAM), or other knownmemory device, wherein the at least one memory device 402 includes atleast one conductive via fabricated using the methods of the presentinvention. The memory device 402 is operatively coupled to amicroprocessor 404 that may be programmed to carry out particularfunctions as is known in the art.

The above-illustrated embodiments of the present invention discloseelectrical interconnects in the foam of through-vias that may befabricated using low-cost materials, requiring simple methods, andresulting in robust electrical interconnects that are substantially freeof voids and keyholes. Although the present invention has been depictedand described with respect to various exemplary embodiments, variousadditions, deletions and modifications are contemplated from the scopeor essential characteristics of the present invention. Further, whiledescribed in the context of semiconductor devices or interposers, theinvention has utility for forming electrical interconnects in any deviceor component fabricated with semiconductor components. The scope of theinvention is, thus, indicated by the appended claims rather than theforegoing description. All changes that come within the meaning andrange of equivalency of the claims are to be embraced within theirscope.

1. A method for forming a conductive interconnect in a substrate,comprising: etching at least one blind via in a first surface of asubstrate, the at least one blind via extending toward an opposite,second surface of the substrate; passivating surfaces of the at leastone blind via with an oxide layer to form at least one passivated blindvia; forming a copper seed layer in the at least one passivated blindvia; filling remaining space within the at least one blind via with aconductive material formed on the copper seed layer; and performing anabrasive planarization process to the second surface of the substrate toexpose the conductive material filling the remainder of the at least oneblind via.
 2. The method of claim 1, wherein forming the copper seedlayer comprises sputtering copper.
 3. The method of claim 1, whereinfilling remaining space within the at least one blind via with theconductive material comprises introducing copper into the remainingspace within the at least one blind via.
 4. The method of claim 3,wherein introducing copper comprises plating copper.
 5. A method forforming a conductive interconnect in a substrate, comprising: forming atleast one blind via in a first surface of a substrate; passivatingsurfaces of the at least one blind via with an oxide layer; forming aseed layer comprising copper over the oxide layer; forming conductivematerial on the seed layer to fill remaining space within the at leastone blind via; and abrasively planarizing an opposite, second surface ofthe substrate to expose the conductive material filling the remainder ofthe at least one blind via.
 6. The method of claim 5, wherein formingthe seed layer comprises forming a copper seed layer.
 7. The method ofclaim 6, wherein forming the copper seed layer comprises sputteringcopper.
 8. The method of claim 5, wherein forming conductive materialcomprises plating the conductive material onto the seed layer.
 9. Themethod of claim 8, wherein plating the conductive material comprisesplating a conductive material including copper onto the seed layer. 10.The method of claim 5, wherein forming conductive material comprisesforming conductive material comprising copper on the seed layer.
 11. Asemiconductor device, comprising: a substrate including a first surfaceand an opposite second surface; at least one blind via formed in thefirst surface of the substrate; a passivation layer comprising an oxideover surfaces of the at least one blind via; a copper seed layer overthe seed layer; and a conductive material contacting the seed layer. 12.The semiconductor device of claim 11, wherein the passivation layercomprises a silicon oxide.
 13. The semiconductor device of claim 11,wherein the conductive material comprises copper.
 14. The semiconductordevice of claim 13, wherein the conductive material comprising coppersubstantially fills a volume circumscribed by the seed layer.